High-temperature electric heater



I. PHELPS.

HIGH TEMPERATURE ELECTRHI HEATER.

APPLICATION TILED H:B. 20,1919.

Patnted Jan. 3, 1922.

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WITNESSES: v

S. I. PHELPS.

HIGH TEMPERATURE ELECTRIC HEATER. APPLICATION FILED FEB. 20, I919.

1,;102,37 Patented Jan. 3,1922.

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SE'BRING I. PHELPS, OF WILMETTE, ILLINOIS.

HIGH-TEMPERATURE ELECTRIC HEATER.

Specification ofLetters Patent.

Patented Jan. 3, 1922.

Application filed February 20, 1919. Serial No. 278,119.

To all whom it may concern: 1

Be it known that I, SEBRING I. PHELPS, a citizen of the United States of America,

and a resident of Wilmette, county of Cook,

and is the frequency of renewals of the resistance ribbons or wire, caused by fusing or disintegration of the resistance when operated at the necessary temperature to compete with flame stove heat.

It is also necessary to build up this hightemperature within a diameter or square of 8 inches'or less, in order to accommodate the ordinary cooking utensils, most of which a are of a diameter less than 8 inches, exceptperhaps some frying pans and teakettles- There are listed for sale electric heating units or burners, commonly called hotplates, of 10 and 12 inches diameter, which are claimed to operate at ashigh as 2000 watts, but none as small as 8 inches are claimed to operate at more than 1500 watts.

The life or durability of heating units or hotplates is very uncertain even on intermittent use, making the cost of renewals of the resistance expensive and annoying, and even 1500 watts in an 8-inch diameter does not contain sufficient heat units to compete successfully in speed and service with gas or flame heat "in corresponding or smaller diameters, and where such large burners or hotplates as 10 inches are used to secure 1800 or 2000 watts, no efiiciency or economy is secured if a utensil of but seven or eight inches diameter is being used, as the extra exposed surface dissipates electric heat at a loss.

The main objects of this invention are to provide a stove or heater of improved form adapted for greater concentration of heat without injury to the generating elements, so as to compete and compare favorably with flame stove heat and at the same time eliminate or greatly reduce the usual necessary frequent renewals of the heat-generating elements; to provide an improved form and arrangement of heater elements or parts and protective means thereforrto provide improved means for conducting the heat generated in a remote part of the generator circuit to a limited area or oint of heat application; and to provide or an assemblage of heat generators and good heat conductors adapted and arranged to deliver a powerful concentration of heat to a limited area of application.

An illustrative embodiment; of this invention is shown in the accompanying drawin s, in which 1g. 1 is a top plan of the heater assembled complete. F Fig. 2 is a section on the line 22 of Fig. 3 is a front elevationof the heater with the medial part of the front wall broken away to show-the interior.

Fig. 4 is an enlarged vertical sectional deta1l of one of the heater units.

Flg. 5 is an end view of an upper corner of one of the units.

Fig. 6 is a top view of one end of one of the units.

Fig. 7 shows a modification.

In the construction shown in the drawings, the heater comprises mainly a frame 1, a plurality of heater units or elements 2.

Said frame 1, for convenience in manufacture and for-commercial reasons, is preferably rectangular in plan. The body part of the frame is of sufficient height to accommodate the thin heater plates 2 arran ed,

uprightly side by side, said body part being supported well above the table or other support, not shown, by means of the frame legs 5 formed integrally within the frame.

Each heater unit 2 comprises, in combination, a central core f refractory material such as mica, asbestos, or the like in sheet form, a heatenerating conductor 7 wound thereon, a pair of metallic heat-conducting armor plates 8 and 9, and a pair of insulator plates 10. The plates '8 and 9 are disposed on plppositesides of said plate 6 and insulate from the resistance 7 by the refractory sheets 10. The plates 8 and 9 are tightly clampedto ether and serve to conduct the heat rapid y away from said generating wire and transmit it to the top of the heater where the plate-edges lie in substantially the same plane. The upper edge of each unit is provided with a horizontal flange 11 integral with one of .the heat conductors, for instance plate 8, which provides for more surface contact between the heat-generating units and the utensils so as to more efficiently transmit and distribute the heat to the utensilor other object placed on or above the heater.

In order that different degrees of heat may be readily obtained from the same heater, a switch commonly known as a three heat switch is arranged on the frame and connected in a suitable manner with the several units.

Each plate 8 is provided with an end extension or lug 25 at or near its upper edge adapted to fit in a corresponding vertical slot 26 in the frame bar 27. Just below said lug 25 a narrow strip '28 is provided adapted to fold over the opposite plate 9 for binding the plates together. The lower portion of the unit is also held together by a finger 29 formed on one of the plates 8-and 9 and folded around the other.

In order to concentrate the air'draft and application of heat generally to the usual area represented by an ordinary cooking like, a removable centrally apertured top or cover member 30 is provided. Said top is made of very thin sheet metal and has a circular hole. It is provided-with a downward outer flange 32 adapted to fit over the top of frame 1 and over the end lugs 25;

The frame is preferably enclosed on all sides, but may be left open at the bottom so as to admit an upward. draft of air, which,

- becoming highly heated, transmits heat ef fectually to any object on the heater.

There are numerous ways in which the device as a whole maybe wired. A suitable switch (not shown) is connected by leads to central binding posts or fasteners 22', 23, and 24:. Frompost 22' a plurality of distributing leads 35 extend to corresponding fasteners 36 secured to one side of the frame.

' Other leads 37 and 38 extend from posts 23' and 24 to fasteners 39 and 40 respectively secured to the opposite side of the frame. Each element 2 has. one of its terminal leads secured to one of the posts 36 and the other to one of the posts 39 or 40. Cross bars 42 extend across the bottom and support the terminals 22', 23', and 24 which are mounted thereon. r

The operation of the device is controlled by the switch which may be thrown to one or the other of its positions to give either a low heat, medium heat or high heat, depending upon the purpose for which the device is to be used.

Plain heat-conducting plates 45 may to advantage be disposed alternately with the generating ..-1its 2, as shown in Fig. 8, especially '1 the generator be made relatively deep. In this instance, heat radiating from the lower portion of a unit 2 is absorbed and transmitted upward by the plates 45 and delivered through its flanged upper edge to the utensil or other object to be heated. B this means, it is practical to maintain a Sui ficient temperature at the point or surfaceof application, with a lower excess degree of heat at the point of generation, and thereby avoid the burn-outs that occur at the higher temperatures.

In order to demonstrate my invention and to show that it is practicable to reduce the necessity of frequent renewals and to secure a very much higher heat than obtained'heretofore in such devices, I have designed and.

fully tested this method of securing from 10,00 to 1500 Watts in a 6-inch, 2000 to 3000 watts in anS-inch, and 3000 to 4000 watts in a 10-inch square heater. v

Briefly summarized, my method consists in winding on a fiat surface of insulation material, flat ribbon or other resistance material so that eachwinding forms a complete unit operating at a low temperature in itself. By spacing closely together a multiple of these low-temperature units, I secure a very high generating capacity and efficient temperature, within an economic operating space.

I have used these units in multiple, at about 250 watts each, hanging or supported Vertically, rather than horizontally as has been the common practice in the use of flat resistance or coil resistance, and am securing temperatures from 331]; to 100% greater than have heretofore been secured, to my knowledge, within so small diameters or squares'as 6 to 8 inches.

By making use of. heat conductivity and radiation in arranging this device, I gain a large efiiciency over those units where radiation only is secured. A decided advantage is secured by the use of these low-temperature units, for each unit may be inserted or taken from its position without disturbing any other unitor even throwing off the current. If any one unit should fuse, it would do so within itself, and the.hotplate or burner has lost but a very small part of its efiiciency,-even if'no new unit were im-' mediately inserted.

The .units are instantly interchangeable, and it'is both possible and practical to take an 8-inch frame, forexample, and insert enough units to make, say, 1000 watts, or to insert enough to' make 1500, 2000, 2500, or

3000, or' if it is a 3000-watt unit, enough units can be removed (even while the electric current is on) to reduce the wattage and temperature accordingly,.to any practical wattage desired. 7

Another advantage, and this is a great advantage, is due to the fact that the volttically spaced relation so that age in the same central times as much as 10 and night service.

Heretofore, electric burners or hotplates have been and are commonly wound for a voltage fluctuation of but 2 to 4 volts. With this new burner or hotplate (units in multiple) the low temperature of'each unit in the multiple will permit a voltage fluctuation of 25 volts without danger of fusing the winding (resistance), yet give very high efiiciency even if the voltage should drop instead of advance, and it usually drops more frequently than it advances over the normal voltage,

Although but two specific embodiments of this invention are herein shown and de-. scribed, it will be understood that other embodiments are possible, and numerous details of the constructions shown may be altered-'or omitted, without departing from the spirit of'this invention as defined by the following claims.

I claim':

1. A culinary electric heater comprisinga station varies, somevolts during the day frame, a plurality of separately constructedheating units arranged sideiby side on said frame so that they all have one face or edge thereof disposed in substantially the same horizontal plane, thereby forming a support upon which a culinary utensil may rest with the bottom-thereof in direct contact with each of said units, each of said heating units including a resistance winding constructed to operate at a comparatively low wattage, and electric conductors on said frame connecting all vof said units in parallel with each other, and with a source of electricity.

2. A culinary electric heater comprisinga frame, a plurality. of separately constructed heating units each of flat rectangular shape arranged side by side on said frame in verthey all have one edge disposed in substantially the same horizontal plane, thereby forming a support upon which a culinary utensil may rest with the bottom thereof in direct contact with each of said units, each of said heating unitsincluding a resistance winding constructed to operate at a comparatively low wattage, and electric conductors on said eachother and with frame connectingall of said units in parallel with each other and with a source of electricity. I

- 3. A culinary electric heater comprisinga frame, a plurality of separately constructed heating units each of flat rectangular shape arranged side by side on'said frame in vertically spaced relation so that they all have one edge disposed'in substantially the same horizontal plane thereby forming a support upon which a culinary utensil may rest with the bottom thereof in direct contact with each'of said units, each of said units including a resistance winding constructed so as to operate at a wattage lower than that which of itself would heat the resistance winding to a state of incandescency, and electric conductors on said frame connecting all of said units in parallel with a source of electricity.

4. An electric heater, comprising a frame, a plurality of separately formed heat-generating units, said frame having notches formed in opposite sides thereof, and shoulders on the ends of said units adaptedto engage the respective notches for supporting said units in vertically disposed relation-on said frame.

5. In an electric heater, the combination of a frame, a plurality of heat-generating units each comprising a flat core member wound with a resistance material and housed between a pair of metal plates rigidly secured together, and coacting means on said frame and each of said units for supporting said units vertically in spaced relation on said frame, one of the plates of each of said units having a transversely disposed flange formed on the upper end thereof, and means forsupportingrsaid units in vertical spaced relation on said frame whereby said flanges are disposed in substantially the same horizontal plane.

6. In an electric heater of the character described, a combination of a frame, a plurality of heat-generating resistance conductors vertically arranged on said frame, and a plurality of heat conductors interspersed with said resistance conductors.

Signed at Chicago this 15th day of F eb.,

SEBRING I. PHELPS. 

